Pontiac Fiero Chassis - Fiero Stretch

When manufacturers in the kit car industry started cranking out Lamborghini and Ferrari replicas based on the Fiero platform, designers knew the chassis needed a stretch to achieve a more accurate look. The Fiero wheelbase is 93.4 inches, while a Lambo Countach is 96.5 inches, a Diablo is 104.3 inches, and a Ferrari Testarossa is 100.4 inches.

Although building on a standard-length Fiero chassis is much cheaper, many builders will not settle for the shortened look. There are many ways to lengthen the chassis, ranging from professional to suicidal, and weve seen em all.

The hardest part of the job is making sure everything gets lined up straight again when the car is complete. You will also usually need to widen the chassis or suspension to more closely match the track of the original.

Another problem is keeping the chassis square when the top is cut off (necessary with most Lambo kits). The standard Fiero relies on the top for much of its rigidity, so when the top is removed, the chassis will warp out of alignment if it is not firmly bolted to a rigid, steel chassis table. If you us the standard four-banger or 2.8L V-6, you might not notice misalignment as readily as you would with a fire-breathing turbo or a V-8 swap, but it will probably not track straight, and braking and tire wear could be adversely affected.

When we got a call from John Austin at Austin Conversions, we were excited to hear he was planning to stretch a Fiero 11 inches before installing one of his Design One Northstar swaps. Austin and partner Kevin Leslie have been making these installations for several years now, and they really turn the mild-mannered Fiero into a serious Corvette basher. Austin installed a D&R Diablo kit on an 84 base model Fiero for customer Phil Craine. He recruited Terry Fisher, who normally fills his time building NASCAR trucks and selling heavy-duty fasteners, to help with the fabrication.

Fisher has a professional chassis surface table in his spa-cious shop, just what was needed to keep the Fiero square while it was being dissected. A chassis table is constructed of thick steel to provide a perfectly level surface on which to attach a chassis so you can accurately measure and align all the components. It is also heavy enough to not be affected by changes in temperature or weather, which temporary wooden jigs can be. Working on an uneven shop floor or with flimsy wooden jigs is a recipe for chassis gremlins.

The Diablo kit is one of the most difficult to stretch, as a great deal of the original Fiero chassis must be cut away for body clearance, including quite a bit of the firewall. This means Austin and Fisher had to back-half the chassis and make an entirely new rear subframe from scratch. Some kits, such as Ferrari Testarossa and F355 replicas, do not require as much cutting and can be stretched more easily, requiring only lengthening of the chassis with extensions.

After all the stretch work, the resulting car will run like a thoroughbred and be better reinforced should the worst occur. Heres how this stretch was done.